MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

⇐ BackProceed to Checkout ⇒
There are no items in this cart.
Continue Shopping
Menu
Grade: 12th pass 
        
An object moving at speed 40cm/sec towards a concave mirror of focal kenght 20cm.When the object is at distance 60cm,the speed of image is
 
8 months ago

Answers : (1)

View Solution
Piyush Kumar Behera
433 Points 
							
\frac{1}{f}=\frac{1}{u}+\frac{1}{v}
Differentiating the expression w.r.t. time
0=\frac{1}{v^{2}}\frac{du}{dt}+\frac{1}{u^{2}}\frac{dv}{dt}
\frac{dv}{dt}=-\frac{v^{2}}{u^{2}}\frac{du}{dt}
 
Just find the final position of the image by using the mirror formula...
\frac{1}{-20}=\frac{1}{-60}+\frac{1}{v}
 
Solving we get
v = – 30 cm
 
Now using this formula we get
\frac{dv}{dt}=-\frac{v^{2}}{u^{2}}\frac{du}{dt}
\frac{dv}{dt}=-\frac{(-30)^{2}}{(-60)^{2}} *40
 
\frac{dv}{dt}=-\frac{1}{4}*40
\frac{dv}{dt}=-10 cm/sec
 
So the velocity of the image is 10 cm/sec opposite to the direction of the velocity of object.
 
Piyush Kumar Behera
IIT Dhanbad
 
 
7 months ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Other Related Questions on Modern Physics

The dusintigration constant of a radio active element ia 0.00231 per day.find half light and everage... Answer & Earn Cool Goodies
calculate the wavelength in the visible spectrum (3500-7000)angstrom which coincide with the... Answer & Earn Cool Goodies
Why most of solids in nature are crystalline solids? Explain briefly.
Potassium isotope has a half life of 1.37 × 10 raise to 9 years and decays to an isotope of Argon...
The pressure exerted by 6g of methane gas ina 0.03m3 vessel at 129℃is
View all Questions »


Course Features

  • 101 Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution


Course Features

  • 110 Video Lectures
  • Revision Notes
  • Test paper with Video Solution
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Previous Year Exam Questions


Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers To Win!!! Click Here for details